<code>
create or replace 
FUNCTION F_ADD 
   (v_a in number,
    v_b in number)
   RETURN NUMBER AS 
  v_sum number;     
BEGIN  
  v_sum := v_a + v_b;
  dbms_output.put_line('Ergebnis ' || v_sum);
  RETURN v_sum;
END F_ADD;
</code>

select f_add(3,7) from dual